Apogee is the highest point of something, where it is greatest or most successful. Nadir, meaning the lowest point or the point of the greatest adversity or despair, is its antonym.

Unjustified is an antonym of warranted.

Epiphany means insight or realization. Secret is an antonym of epiphany.

Archetypal means having all the important qualities that make somebody or something a typical example of a particular kind of person or thing. The word unique is its antonym.